When the Maltese-flagged bulk carrier Vitaspirit crashed into an 18th-century mansion on the Bosphorus Strait in April, it not only meant significant cultural loss for Istanbul, but also provided fodder for the supporters of the Kanal Istanbul project.

The Bosphorus, a narrow sea channel that is about 32km-long, is a notoriously difficult waterway to navigate.

“The difficulty comes from its narrowness, sharp curves and the continuous current coming to the Marmara Sea from the Black Sea, which is half a metre higher,” said Cahit Istikbal, a pilot and president of the Turkish maritime safety association.

In 2017, about 43,000 ships crossed the Bosphorus according to the Turkish government, making it one of the busiest waterways in the world. Istikbal estimates that at least two ships run aground every year trying to cross it.

“If the question is decreasing the risk of collision in the strait of Istanbul, then yes, Kanal Istanbul will serve its purpose,” added Istikbal.

But when it comes to the environmental and social costs of what President Erdogan dubbed his “crazy project”, the consensus falls away.

Opponents of the project claim its environmental toll, in the pristine parts of the city, is too heavy to ignore and has not been studied properly.

Building the canal will effectively trap 8 million people on a new artificial island in a city notoriously prone to earthquakes and will threaten the delicate balance of currents and chemicals from the Black Sea to Marmara Sea linked to the Bosphorus.

There is also concern about the archaeological sites bordering the canal route, such as the Yarimburgaz caves, dating from the Paleolithic Era and considered the oldest human settlements in Turkey.

The site currently lies unattended next to a highway north of Küçükçekmece, a lake bordering the Marmara Sea that will mark the end of the new canal.

Local communities in villages along the canal route also wait for their fate to be announced.

“We are not against the canal. We can sacrifice our land for our state,” said Fikri Bekbaş, a citizen from Sazlibosna village.

“We just want the state to buy the land at its real value, not at cheap prices only to transfer it to someone else. If the village stays we want to stay. If it disappears we have no other choice but leave.”

Speculation has built since Turkey’s transport minister announced the route of the canal in January. Cihad Aksoy, from FGA Grup real estate agency, estimated prices per square metre have gone up by at least 50 per cent in some areas.

“They just buy the land and wait,” he said, referring to investors. “There are both local and foreign. Among the foreign investors, 70 per cent are Arabs, from Qatar and Saudi Arabia.”

Cihan Baysal, an independent researcher specialising in housing rights and a vocal critic of Kanal Istanbul, said the canal is just a real estate project.

“Turkey’s economy only works with the help of the construction and real estate sectors,” Baysal said. “The authorities need the canal to turn the gears on the economy, especially before the upcoming elections.”

Turkey has embarked on a series of infrastructure projects in the past few years, building a third bridge across the Bosphorus and a third airport for Istanbul, slated to open in October.

Openly criticising such infrastructure projects, in a country where authorities are obsessed with development and have become less tolerant of dissent, carries its own risks. In a 2013 speech, Erdogan suggested protesters “live in the forest”.

“This is the project of the century and Erdogan is inscribing his name and ideology of growth and development on it,” Baysal said. “So if you are against it, you are against the country.”